#include <stdio.h>
int main()
{
	int n, h, max=0, first=1001, i, last=1001;
	scanf("%d", &n);
	for (i=0; i<n; i++)
	{
		scanf("%d", &h);
		if(h<=last)
		{
			if(last-first>max)
				max=last-first;
			last=h;
			first=h;

		}
		else
		{
			last=h;
			if(last-first>max)
				max=last-first;
		}
	}
	printf("%d", max);
	return 0;
}